2. Academic Validation
  3. The human pseudouridine synthase PUS7 recognizes RNA with an extended multi-domain binding surface

The human pseudouridine synthase PUS7 recognizes RNA with an extended multi-domain binding surface

  • Nucleic Acids Res. 2021 Nov 18;49(20):11810-11822. doi: 10.1093/nar/gkab934.
Julia Guegueniat 1,  Levon Halabelian 2 3,  Hong Zeng 2,  Aiping Dong 2,  Yanjun Li 2,  Hong Wu 4,  Cheryl H Arrowsmith 2 5,  Ute Kothe 1 6
Affiliations

Affiliations

  • 1 Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, University of Lethbridge, AB, T1K 3M4, Canada.
  • 2 Structural Genomics Consortium, University of Toronto, Toronto, ON, M5G 1L7, Canada.
  • 3 Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, M5S 1A8, Canada.
  • 4 Protein Technologies Center, St Jude Children's Research Hospital, Memphis, TN 38105, USA.
  • 5 Princess Margaret Cancer Centre and Department of Medical Biophysics, University of Toronto, Toronto, ON, M5G 2M9, Canada.
  • 6 Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada.
PMID: 34718722 DOI: 10.1093/nar/gkab934
Abstract

The human pseudouridine synthase PUS7 is a versatile RNA modification Enzyme targeting many RNAs thereby playing a critical role in development and brain function. Whereas all target RNAs of PUS7 share a consensus sequence, additional recognition elements are likely required, and the structural basis for RNA binding by PUS7 is unknown. Here, we characterize the structure-function relationship of human PUS7 reporting its X-ray crystal structure at 2.26 Å resolution. Compared to its Bacterial homolog, human PUS7 possesses two additional subdomains, and structural modeling studies suggest that these subdomains contribute to tRNA recognition through increased interactions along the tRNA substrate. Consistent with our modeling, we find that all structural elements of tRNA are required for productive interaction with PUS7 as the consensus sequence of target RNA alone is not sufficient for pseudouridylation by human PUS7. Moreover, PUS7 binds several, non-modifiable RNAs with medium affinity which likely enables PUS7 to screen for productive RNA substrates. Following tRNA modification, the product tRNA has a significantly lower affinity for PUS7 facilitating its dissociation. Taken together our studies suggest a combination of structure-specific and sequence-specific RNA recognition by PUS7 and provide mechanistic insight into its function.

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